δ13C stratigraphy of the Proterozoic Bylot Supergroup, Baffin Island, Canada: implications for regional lithostratigraphic correlations

1999 ◽  
Vol 36 (3) ◽  
pp. 313-332 ◽  
Author(s):  
Linda C Kah ◽  
Anne G Sherman ◽  
Guy M Narbonne ◽  
Andrew H Knoll ◽  
Alan J Kaufman
Keyword(s):  
Carbon Isotope ◽  
Record Values ◽  
Time Correlation ◽  
Published Data ◽  
Baffin Island ◽  
Isotopic Data ◽  
Carbon Isotopic ◽  
Somerset Island ◽  
Interval Comparison

The Bylot Supergroup, northern Baffin Island, contains >1500 m of platform, shelf, and slope carbonates deposited between ~ 1270 and ~ 723 Ma. Limited chronostratigraphic data have led to the broad correlation of the Bylot Supergroup with predominantly Neoproterozoic successions in northern and western Laurentia; yet, detailed correlation has been impossible given biostratigraphic and lithostratigraphic limitations. Carbon-isotope chemostratigraphy represents a potential dataset to constrain such interregional correlations. Carbon isotopic data from the Bylot Supergroup and broadly coeval successions from Somerset Island and northwest Greenland reveal distinct stratigraphic trends in δ13C, with intervals of moderate 13C enrichment (+3.5 ± 1‰) punctuated by excursions to slightly negative values (-1.0 ± 1‰). Although the scale of the observed variation is muted relative to Neoproterozoic standards, the dissimilarity of values to those recorded in northwestern Laurentia suggests that these strata delineate a discrete depositional interval. Comparison of isotopic values with published data indicates that δ13C values between approximately -1.0 and +4.0‰ are characteristic of the interval between ~ 1300 and ~ 800 Ma. This pattern is distinct from that of younger Neoproterozoic successions, which typically record values >+5‰, and older Mesoproterozoic successions, which record values near 0‰, and suggests that these moderately positive values may be useful for broad time correlation. Compilation of new and published data permits the tentative reconstruction of a global Mesoproterozoic carbon isotopic curve.

Carbon isotope stratigraphy and the problem of a pre-Tommotian Stage in Siberia

2001 ◽  
Vol 138 (4) ◽  
pp. 387-396 ◽  
Author(s):  
ARTEM KOUCHINSKY ◽  
STEFAN BENGTSON ◽  
VLADIMIR V. MISSARZHEVSKY ◽  
SHANE PELECHATY ◽  
PETER TORSSANDER ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Siberian Platform ◽  
Lower Cambrian ◽  
Isotopic Data ◽  
Sequence Stratigraphic ◽  
Anabar Uplift ◽  
Carbon Isotopic ◽  
The North ◽  
Isotope Stratigraphy ◽  
Isotopic Variations

Carbon isotopic oscillations are useful to elucidate the stratigraphy and biogeochemical events around the Precambrian–Cambrian transition. New isotopic data from the Manykaj and Emyaksin formations of the eastern Anabar Uplift (Siberia) help to correlate the Lower Cambrian and Neoproterozoic–Cambrian transitional beds across the Siberian Platform. The similarity of trends and amplitudes of the carbon isotopic curves, together with biostratigraphic and sequence-stratigraphic markers from the Anabar Uplift, provide a precise correlation with the southern part of the Siberian Platform. Diagenesis of argillaceous limestones of the Emyaksin Formation has apparently not affected the primary isotopic variations. The resulting curve is nearly identical in sections about 100 km apart in the Tommotian–Atdabanian portion of the formation. Relatively frequent and pronounced isotopic oscillations in the lower beds of the Emyaksin Formation fit between features I and II of the southern Siberian isotopic reference scale but are undetected therein owing to the depositional hiatus at the base of the Tommotian Stage in its type section. This confirms the transgressive onlap from the north suggested by previous studies, and makes the appearance of the Cambrian skeletal fossils on the Siberian Platform less abrupt. The hiatus in the south appears to embrace at least two biostratigraphic zones as recognized in the north. The case is strengthened for a pre-Tommotian Cambrian Stage in Siberia, the biostratigraphic framework for which has been elaborated earlier.

Katian (Upper Ordovician) carbon isotope chemostratigraphy in the Neixiang area, central China: implications for intercontinental correlation

2019 ◽  
Vol 156 (12) ◽  
pp. 2053-2066 ◽  
Author(s):  
Xiuchun Jing ◽  
Svend Stouge ◽  
Yufeng Tian ◽  
Xunlian Wang ◽  
Hongrui Zhou
Keyword(s):  
Sea Level ◽  
Carbon Isotope ◽  
Central China ◽  
Sea Level Changes ◽  
Isotopic Data ◽  
Upper Ordovician ◽  
Long Distance ◽  
Carbon Isotopic ◽  
The North ◽  
Main Driver

AbstractThe Katian (Upper Ordovician) Shiyanhe Formation at the Sigang section, Neixiang area, Henan Province, central China, has been investigated for carbon isotope (δ13Ccarb) chemostratigraphy. The carbon isotopic data document signal between the two major Ordovician positive shifts in δ13C, the early Katian Guttenberg and the Hirnantian excursions. The Kope (Ka1/2), Fairview (Ka2/3), Waynesville (Ka3/4), Whitewater (Ka4) excursions and a doubtful Elkhorn (Ka4) excursion are identified herein. The continuous and well-defined conodont zonal succession of the Sigang section provides a secure biostratigraphic framework for the mid-late Katian carbon isotope chemostratigraphy in China. Correlation between carbon-isotope data curve and the relative sea-level changes shows no clear correspondence, and hence the sea-level change is probably not the main driver of δ13C excursions during the Katian. Intercontinentally, the mid–late Katian carbon isotope excursions, identified mainly in the North American and Baltoscandian successions, are useful for improving long-distance stratigraphic correlations. This further suggests that these excursions represent global perturbations in the carbon cycle.

scholarly journals Constraints on ocean circulation at the Paleocene–Eocene Thermal Maximum from neodymium isotopes

2015 ◽  
Vol 11 (3) ◽  
pp. 2557-2583 ◽  
Author(s):  
A. N. Abbott ◽  
B. A. Haley ◽  
A. K. Tripati ◽  
M. Frank
Keyword(s):  
Ocean Circulation ◽  
Deep Water ◽  
Deep Ocean ◽  
Published Data ◽  
Isotopic Data ◽  
Carbon Isotopic ◽  
Atmosphere System ◽  
Thermal Maximum ◽  
Ocean Atmosphere ◽  
Deep Ocean Circulation

Abstract. Global warming during the Paleocene Eocene Thermal Maximum (PETM) ~55 million years ago (Ma) coincided with a massive release of carbon to the ocean–atmosphere system, as indicated by carbon isotopic data. Previous studies have argued for a role for changing ocean circulation, possibly as a trigger or response to climatic changes. We use neodymium (Nd) isotopic data to reconstruct short high-resolution records of deep-water circulation across the PETM. These records are derived by reductively leaching sediments from seven globally distributed sites and comparing data with published data from fossil fish debris to reconstruct past deep ocean circulation across the PETM. The Nd data for the leachates are interpreted to be consistent with previous studies that have used fish teeth and benthic foraminiferal δ13C to constrain regions of convection. There is some evidence from combining Nd isotope and δ13C records that the three major ocean basins may not have had substantial exchanges of deep waters. If the isotopic data are interpreted within this framework, then the observed pattern may be explained if the strength of overturning in each basin varied distinctly over the PETM, resulting in differences in deep-water aging gradients between basins. Results are consistent with published interpretations from proxy data and model simulations that suggest modulation of overturning circulation had an important role for global recovery of the ocean–atmosphere system after the PETM.

Climate and land-use effects on hydrological and vegetation signals during the last three millennia: Evidence from sedimentary leaf waxes in southwestern Morocco

The Holocene ◽  
2021 ◽  
pp. 095968362098805
Author(s):  
Asmae Baqloul ◽  
Enno Schefuß ◽  
Martin Kölling ◽  
Lydie Dupont ◽  
Jeroen Groeneveld ◽  
...  
Keyword(s):  
Land Use ◽  
Carbon Isotope ◽  
Vegetation History ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Economic Stress ◽  
Published Data ◽  
Leaf Waxes ◽  
Argan Tree ◽  
Precipitation Changes

The southwest of Morocco is considered to be an area of refuge within the Mediterranean region, hosting the endemic tropical Argan tree. This region is presently subject to severe droughts, desertification and land degradation, and likely facing increased climate variability and socio-economic stress in the future. Here, we use the stable hydrogen and carbon isotope composition (δD and δ13C) of plant-waxes in a high-resolution marine sediment core (GeoB8601-3) collected off Cape Ghir in southwestern Morocco, in combination with published data on pollen and XRF element ratios from the same archive. We aim to reconstruct the hydroclimate and vegetation history during the last 3000 years. Stable carbon isotope compositions of leaf waxes (δ13Cwax) show that natural vegetation in southwestern Morocco consists of C3 plants. Minor variations in δ13Cwax were positively correlated to changes in stable hydrogen isotope compositions of leaf waxes (δDwax) before 700 CE. Changes in rainfall amounts and water use efficiency indicate a clear vegetation response to precipitation changes and thus to climate forcing. After 700 CE, δDwax and δ13Cwax became de-coupled suggesting that the plant wax discharge and their isotope signals were no longer solely controlled by climate; the waxes likely mainly originate from the lowlands and carry an enriched (dry) δD signal but a depleted 13C signature. The depletion of δ13Cwax correlates with the increase of Argan pollen concentration in the record. The period between ~700 and 900 CE coincides with the Arabization of Morocco which had an impact on the demographic composition of the country leading to new agricultural habits and, as a result, on the land-use triggering a higher erosion of lowland material by the Souss River.

Long-term Aptian marine osmium isotopic record of Ontong Java Nui activity

Geology ◽  
2021 ◽  
Author(s):  
Hironao Matsumoto ◽  
Rodolfo Coccioni ◽  
Fabrizio Frontalini ◽  
Kotaro Shirai ◽  
Luigi Jovane ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Volcanic Eruptions ◽  
Hydrothermal Activity ◽  
Published Data ◽  
Isotopic Data ◽  
Oceanic Plateaus ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Isotopic Records

The early to mid-Aptian was punctuated by episodic phases of organic-carbon burial in various oceanographic settings, which are possibly related to massive volcanism associated with the emplacement of the Ontong Java, Manihiki, and Hikurangi oceanic plateaus in the southwestern Pacific Ocean, inferred to have formed a single plateau called Ontong Java Nui. Sedimentary osmium (Os) isotopic compositions are one of the best proxies for determining the timing of voluminous submarine volcanic episodes. However, available Os isotopic records during the age are limited to a narrow interval in the earliest Aptian, which is insufficient for the reconstruction of long-term hydrothermal activity. We document the early to mid-Aptian Os isotopic record using pelagic Tethyan sediments deposited in the Poggio le Guaine (Umbria-Marche Basin, Italy) to precisely constrain the timing of massive volcanic episodes and to assess their impact on the marine environment. Our new Os isotopic data reveal three shifts to unradiogenic values, two of which correspond to black shale horizons in the lower to mid-Aptian, namely the Wezel (herein named) and Fallot Levels. These Os isotopic excursions are ascribed to massive inputs of unradiogenic Os to the ocean through hydrothermal activity. Combining the new Os isotopic record with published data from the lowermost Aptian organic-rich interval in the Gorgo a Cerbara section of the Umbria-Marche Basin, it can be inferred that Ontong Java Nui volcanic eruptions persisted for ~5 m.y. during the early to mid-Aptian.

Nd isotopic characteristics of metamorphic and plutonic rocks of the Coast Mountains near Prince Rupert, British Columbia

1998 ◽  
Vol 35 (5) ◽  
pp. 556-561 ◽  
Author(s):  
P J Patchett ◽  
G E Gehrels ◽  
C E Isachsen
Keyword(s):  
British Columbia ◽  
Volcanic Rocks ◽  
Metamorphic Rocks ◽  
Published Data ◽  
Isotopic Data ◽  
Crustal Component ◽  
Coast Mountains ◽  
Crustal Rocks ◽  
Metasedimentary Rocks ◽  
Plutonic Rocks

Nd isotopic data are presented for a suite of metamorphic and plutonic rocks from a traverse across the Coast Mountains between Terrace and Prince Rupert, British Columbia, and for three contrasting batholiths in the Omineca Belt of southern Yukon. A presumed metamorphic equivalent of Jurassic volcanic rocks of the Stikine terrane gives epsilon Nd = +6, and a number of other metaigneous and metasedimentary rocks in the core of the Coast Mountains give epsilon Nd values from +3 to +7. A single metasedimentary rock approximately 3 km east of the Work Channel shear zone gives a epsilon Nd value of -9. Coast Belt plutons in the traverse yield epsilon Nd from -1 to +2. The Omineca Belt plutons give epsilon Nd from -10 to -17. All results are consistent with published data in demonstrating that (i) juvenile origins for both igneous and metamorphic rocks are common in the Coast Belt; (ii) representatives of a continental-margin sedimentary sequence with Precambrian crustal Nd are tectonically interleaved in the Coast Mountains; (iii) Coast Mountains plutons can be interpreted as derived from a blend of metamorphic rocks like those seen at the surface, or as arc-type melts contaminated with the older crustal component; and (iv) Omineca Belt plutons are dominated by remelted Precambrian crustal rocks.

scholarly journals Modeling the consequences on late Triassic environment of intense pulse-like degassing during the Central Atlantic Magmatic Province using the GEOCLIM model

2012 ◽  
Vol 8 (3) ◽  
pp. 2075-2110 ◽  
Author(s):  
G. Paris ◽  
Y. Donnadieu ◽  
V. Beaumont ◽  
F. Fluteau ◽  
Y. Goddéris
Keyword(s):  
Carbon Cycle ◽  
Carbon Isotope ◽  
Carbon Isotopic Composition ◽  
Late Triassic ◽  
Carbonate Production ◽  
Carbon Isotopic ◽  
Central Atlantic Magmatic Province ◽  
Igneous Provinces ◽  
Central Atlantic ◽  
Sedimentary Carbon

Abstract. The Triassic-Jurassic boundary (TJB) is associated with one of the five largest mass extinctions of the Phanerozoic. A deep carbon cycle perturbation and a carbonate production crisis are observed during the late Triassic. The Central Atlantic Magmatic Province (CAMP), one of the most important large igneous provinces of the Phanerozoic, emplaced at the TJB. To understand the carbon cycle perturbations observed at the TJB, we investigate the consequences of CO2 degassing associated to the CAMP emplacement on atmospheric and oceanic carbon cycle. The CO2 input within the atmosphere due to volcanism has been modeled using a global biogeochemical cycle box model (COMBINE) coupled with a climate model (FOAM). Weathering fluxes and CO2 equilibrium are constrained by the Rhaetian paleogeography and different scenarios of the CAMP emplacement are modeled. The study focuses (1) on the geological record and the carbonate productions crisis and (2) on the sedimentary carbon isotope record. For point (1), comparison of different modeling scenarios shows that a Gaussian CO2 emission distribution over the duration of the main activity phase of the CAMP fails in reproducing any of the geological observations, mainly the carbonate production crisis observed in the late Rhaetian sediments. Contrastingly, intense degassing peaks lead to successive decrease in carbonate production as observed in the geological record. For point (2), the perturbations of carbon cycle due to the degassing of CO2 with a mantellic carbon isotopic composition of −5‰ do not reproduce the intensity of the observed carbon isotope excursions. This was achieved in our model by assuming a mantellic carbon isotopic composition of −20‰. Even if this hypothesis requires further investigations, such low values may be associated to degassing of carbon from pools of light isotopic carbon located at the transition zone (Cartigny, 2010), possibly linked to setting of large igneous provinces (LIP's). Breakdown of biological primary productivity can also partially account for the sedimentary carbon isotope excursions and for the observed increase of atmospheric pCO2.

Oxygen–carbon isotope composition of Middle Jurassic–Cretaceous molluscs from the Saratov–Samara Volga region and main climate trends in the Russian Platform–Caucasus

2019 ◽  
Vol 498 (1) ◽  
pp. 101-127 ◽  
Author(s):  
Yuri D. Zakharov ◽  
Vladimir B. Seltser ◽  
Mikheil V. Kakabadze ◽  
Olga P. Smyshlyaeva ◽  
Peter P. Safronov
Keyword(s):  
Carbon Isotope ◽  
Middle Jurassic ◽  
Isotope Composition ◽  
Russian Platform ◽  
Volga Region ◽  
Published Data ◽  
Climate Trends ◽  
Late Mesozoic ◽  
Oxygen And Carbon Isotope ◽  
Epipelagic Zone

AbstractOxygen and carbon isotope data from well-preserved mollusc shells and belemnite rostra are presented from the Jurassic (Bathonian, Callovian and Tithonian) and Cretaceous (Aptian, Turonian, Campanian and Maastrichtian) of the Saratov–Samara Volga region, Russia. New data provide information on the resulting trends in palaeoclimate and in palaeoceanography and palaeoecology in the late Mesozoic. Palaeotemperatures calculated from Jurassic–Cretaceous benthic (bivalves and gastropods) and semi-pelagic (ammonites) molluscs are markedly higher than those calculated from pelagic belemnites using oxygen isotopes. This is probably due to various mollusc groups of the Saratov–Samara area inhabiting different depths in the marine basins (e.g. epipelagic v. mesopelagic). Our isotope records, combined with a review of previously published data from shallow-water fossils from the Saratov–Samara area and adjacent regions permits us to infer temperature trends for the epipelagic zone from the Middle Jurassic to Cretaceous in the Russian Platform–Caucasus area. The Jurassic–Cretaceous belemnites from the Russian Platform and the Caucasus have a lower δ13C signature than the contemporaneous brachiopods, bivalves and ammonites.

The use of stable carbon isotope trends as a correlation tool: an example from the Surat Basin, Australia

2016 ◽  
Vol 56 (1) ◽  
pp. 355 ◽  
Author(s):  
Astrid Hentschel ◽  
Joan S. Esterle ◽  
Sue Golding
Keyword(s):  
Carbon Isotope ◽  
Turning Point ◽  
Stable Carbon Isotope ◽  
Stable Carbon ◽  
Δ13c Values ◽  
Carbon Isotopic ◽  
Gas Source ◽  
Rapid Reversal ◽  
Allogenic Processes ◽  
Coal Measures

The Surat Basin’s Middle Jurassic Walloon Subgroup is a productive coal seam gas source in Queensland, Australia. The Walloon Subgroup can be subdivided into the Upper and Lower Juandah coal measures, the Tangalooma Sandstone, the Taroom Coal Measures, and the Eurombah/Durabilla Formation, from top to bottom. Correlation across the basin is challenging due to high lateral variability and lack of extensive stratigraphic markers. The Walloon Subgroup is also, in places, incised by the overlying Springbok Sandstone, sometimes interpreted as far down as the Tangalooma Sandstone. New age dates suggest that the Walloon Coal Measures are Oxfordian in age and mark a period of high rates of Corg production and burial, and an intermittent decrease of atmospheric pCO2. The un- or dis-conformable base of the Springbok Sandstone coincides with a turning point of this supposedly global phenomenon. This study uses organic stable carbon isotope trends as a correlation tool within the Surat Basin’s Walloon Subgroup and its overlying Springbok Sandstone. Analysis of a stratigraphic suite of coal samples from several wells across the Surat Basin shows a gradual enrichment in 13C up section from the Taroom to the Lower Juandah Coal Measures, with the most positive δ13C values within the Upper Juandah Coal Measures. Thereafter there is a rapid reversal to more negative δ13C values for coal samples of the Springbok Sandstone. The upward enrichment occurs well before the shift in maceral composition to increased inertinite content in the coals, suggesting more global allogenic processes are controlling the carbon isotopic trend. The consistency of these trends lends a more confident correlation for sub-units within the Walloon Subgroup, and assists in determining the level of incision disconformity of the Springbok Sandstone.

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